In the manufacture of patterned devices, such as semiconductor chips and chip carriers, the steps of patterning different layers that constitute the finished product are among the most critical and crucial steps involved. This is particularly so in view of the trend toward very high integration densities and smaller devices. With respect to the production of smaller devices below 0.25 .mu.m definition for integrated circuits, it is desirable, if not essential, to employ resist materials that can be used with radiation sources exhibiting short wavelengths. These short radiation sources operate in the x-ray region and include synchrotron and point sources. Also, electron beam lithography is employed for these smaller devices.
However, many of the conventional resist materials that are currently employed commercially are not especially sensitive to x-ray radiation or electron beam radiation. The inherent insensitivity of such resist materials makes the photospeed thereof too slow for practical application employing x-ray or electron beam lithography. More particularly, various compositions based on diazo quinone photoactive compounds do not perform satisfactorily as x-ray resists in view of their poor absorption of x-ray radiation. On the other hand, these resist compositions are widely used for UV radiation lithography.
Attempts to provide x-ray sensitive resists have resulted in what is referred to as chemically amplified resists material. An example of such is a hydroxylated polystyrene backbone, having attached thereto tert. butyl carbonate. Although these materials are sensitive to x-ray lithography, such suffer from the disadvantage that they are extremely sensitive to contaminants, such as degradation by acid and airborne amines. In fact, these chemically amplified resists are prone to poisoning by even ppm levels of contaminants. Therefore, the use of such requires extremely careful control of processing conditions. Because of the complexity in processing, it seems to be desirable to substitute these resists with nonamplified compositions.